Radio receiving system



Nov. 26, 1929.

H. F. ELLIOTT RADIO RECEIVING SYSTEM.

Original Filed Aug. 15. 1925 3 Sheets-Sheet l INVENTOR Ham/d E///bf/ HIS ATTORNEY Nov. 26, 1929. H. F. ELLIOTT RADIO RECEIVING SYSTEM Original Filed Aug. 15, 1925 3 Sheets-Sheet 2 l NVE N To R Ham/d F f///b/f HIS ATTORNEY NOV. 26, 1929. ELLIOTT 1,737,078

RADIO RECEIVING SYSTEM Original Filed Aug. 15, 1925 3 Sheets-Sheet 3 m jaw I w :4 I I f 7 WWW 7 5 INVENTOR 0r fi/hr/iai BY l /dr'o/d E fW/O/f HIS ATTORNEY Patented Nov. 26, 1929 UNITED STATES PATENT OFFICE HAROLD I. ELLIOTT, OI PALO ALTO, CALIFORNIA, ASSIGNOR, BY DIRECT AND HESNE ASSIGNMENTS, 'I'O VICTOR TALKING MACHINE BEY, A CORPORATION OF NEW JERSEY COMPANY, OF CAMDEN, NEW JER- mmro RECEIVING SYSTEM Application flled August 15, 1925, Serial No. 50,478. Renewed Kay 8,

This invention relates to a system for receiving radio signals, and especially to such a system that is adapted for broadcast reception.

Substantially all receiving systems that are now on the market utilize a device for absorbing or intercepting energy, either in the, form of elevated conductors (antenna), or of a closed loop. These types of absorbing circuits, while not serious y objectionable when used in a commercial way, have never theless inherent disadvantages for amateur or broadcast use. Antennae are expensive, unsightly, especially in closely settled districts, and non-portable; on the other hand, loops abstract but little energy from the surrounding medium, and the energy so abstracted must be greatly amplified, before suflicient volume or intensity of signal can be obtained. Such amplification, unless care be taken in the design of the apparatus, may cause distortion. It has been suggested to use comparatively small indoor aerials; these are inflicient due to the amount of wire which must be used, which increases the resistance of the circuit. When used adjacent the wall, low absorption naturally results, also serving to reduce the efliciency. And of course, both the indoor aerial and loop are unsightly and are not compact.

It is one of the objects of my invention to eliminate the necessity for a special absorbing circuit, so that no separate antenna, loop or wire is required to intercept energy; and to make it possible nevertheless to absorb a considerable amount of energy from the surrounding medium.

It is another object of my invention to provide a compact, readily portable receiving system, capable of immediate and satisfactory use in any location, whether in an isolated spot or in closely built-in sections.

It is still another object of my invention to provide a simple and compact portable radio receiver set, that can be inexpensively constructed.

It is still another object of my invention to utilize the inherent capacity effects between various elements of the receiver system for the absorption of signaling energy from the electromagnetic waves' It is still another object of my invention to provide a receiver in which one or more elements are caused. to serve a double purposethat of an absorbing circuit as well as the usual functions attributed to'the ele ments.

My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of my invention. For this purpose I have shown a few forms in the drawings accompanying and forming part of the present specification. I shall now proceed to describe these forms in detail, which illustrate the general principles of my lnvention; butit is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of my inventlon is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a schematic wiring diagram of a receiving system embodying my invention; and

Figs. 2 to 7 inclusive are modifications of the systemshown in Fig. 1.

In the embodiment shown in Fig. 1, my invention is incorporated in a rece1ver employmg one or more thermionic tubes, although of course other types of receivers can be used. The rectangle 11 is intended to represent the main portions of the receiver, not essential to detail for an exposition of my lnvention. Nevertheless, in order to illustrate clearly the application of my invention,

- I shall describe in detail the circuits immediately adjacent the input side of the receiver. These in the present instance include a tunable circuit 12, comprising an inductance 13 and a variable condenser 14. This circuit is usually arranged to be coupled to an absorbmg clrcuit, as by the aid of coil 13, but in the present instance this usual arrangement is departed from, as will be described later. The thermionic amplifier 15 has its input circuit connected across the condenser 14 of this tunable circuit 12. This input circuit will be hereinafter described in detail. The tube 15 has an electron emittin electrode, such as a heated filament 16, and a cold electrode or plate 17, both enclosed in an evacuated vessel. The filament 16 is arranged to be heated by the passage of current from the usualA battery. The filament 16 is indicated as rounded at 18 and as connected to the ot er elements of the receiver by the aid of binding posts 19 and 20. The late 17 is likewise arranged to be connecte with respect to the other elements by binding post 21.

It is now well understood that if plate 17 is maintained at a potential positive with respect to filament 16, electrons will be attracted from the filament and will thus form a space current. However, the quantity of flow can be controlled by controllln the potential of a point in the space, as by t e aid of the con trol electrode or grid 22. The radio frequency energy renewed in circuit 12 is caused to aifect the relative potentials of this electrode 22 and filament 16, and thereby the space current. This is accomplished for example by connecting one terminal of condenser 14 to grid 22, and the other terminal to filament 16. Thus the input circuit of amnlifier 15 includes grid 22, circuit 12, and filament 16.

The variation in the space current due to variations in the difference of potential between grid 22 and filament 16 is of a much higher order than the potential variations of grid 22, and it is due to this that an amplifying effect is secured. Since the mode of utilizing such amplified energy is now wellknown, further discussion of the input side of the receiver system is unnecessary: nor in fact, is the present invention bound up in any way with the particular circuits already explained. It is suflicient to state that the intercepted radio energy is passed to the input side of the amplifying and detecting system, and is passed out at the output terminals 23 and 24, as amplified audio frequency waves, capable of operatively afiecting a translating device, such as a loud speaker or telephone.

In the present instance, these output terminals are connected to the primary 25 of an audio frequenc transformer 26, the secondary 27 of whic is connected for example to a loud speaker 28, by the aid of a twin connection 29, formed of a pair of individually insulated conductors.

I shall now describe how an ener y intercepting arrangement is provided wilout the addition of further elements. For this purpose, the loud speaker or other translating device 28 can be isolated in a manner to be described, to serve as one element of an absorbing circuit; other elements are the coil 30 formed by winding the conductors 29, which is coupled to the input circuit 12, in this instance inductively, although other forms of coupling can obviously be used. Since there is an inherent capacity coupling,

such as indicated at 31 and 32, between the conductors 29 and the elements of the loud speaker 28 (which preferably, although not necessarily, has a metallic casing to enhance this coupling), it ijseen that the metallic portions of the loud speaker can serve as a condenser plate or capacity area. The earth 18 (or other counterpoise) serves as the other condenser plate of the open absorbin circuit, and this plate is coupled to the absor ing circuit by the inherent capacity couplings 33 and 34 which exists between the conductors 29, the transformer 26, and ground 18. In case these inherent couplings, 31, 32, 33, 34

are insufficient in any instance, the can readily be supplemented by the additlon of condensers.

. The absorbing circuit can now be traced as follows: the metallic elements of translating device 28, capacities 31 and 32, conductors 29 in parallel, coil 30, capacities 33 and 34, and ground 18. It is to be particularly noted that the circuit serving as an absorber or intercepter requires no extraneous elements, except that leads 29 of loud speaker 28 is to be formed into coupling coils 30. For convenience in connecting the loud speaker 28, the leads 29 may have a separable portion 35 arranged to be connected to a stationary binding post structure 36 to-which the pair of parallel conductors forming coils 30, are permanently connected.

It is furthermore to be noted that there can be no appreciable interference between the audio and the radio frequency currents in the circuit serving as an absorber. This is due to the fact that the twin conductors forming coils 3O carry the audio frequency currents in reverse directions through the coils and therefore these currents are neutralized as regards their effect on coil 13. Furthermore,

even if not exactly neutralized, very little audio frequency energy could be transmitted through the air core radio frequency transformer 30-13. Since the audio frequency currents are balanced in coils 30, these coils form no appreciable inductance in the loud speaker circuit.

, It is evident that the underlying principles of my invention can be embodied in many other forms. For example, in Fig. 2, the loud speaker 28 is again represented, with its capacity couplings 31 and 32 as'forming elements of an absorbing circuit. In this instance the radio frequency circuit 37, comprising coil 38 and variable condenser 39, is again arranged to afiect a thermionic amplifier or detector tube 40. The input circuit of this tube, connecting its grid 44 and filament 45, includes a. stopping condenser 41, circuit 37, and by-pass condenser 42. A high resistance leak 43 is connected between the grid and filament' of tube 40, for'well-known purposes. The'filament 45 is arranged to be heated by currentfrom a source 46, such as an A battery. Rectangle 47 is intended to represent some of .the remaining parts of the am lifying and detecting system, which may e of standard design.

The output terminals 48 and 49 connect in this instance to the primary 50 of an audio frequency transformer 51, the secondary 52 of which serves to transmit amplified audio frequency currents to a further thermionic amplifier 53, the input circuit from rid to filament including said secondary. e output circuit extending from plate 54, includes the loud speaker 28 or other translating device, as well as the B battery 55. In order to provide an absorbing circuit, this outputcircuit is coupled to coil 38. In this instance, this coupling is effected conductively, by including an adjustable portion of coil 38 directly in the output circuit of tube 53.

Since the filament circuit is grounded at 56, and since there is a coupling capacity 57 between the leads of loud speaker 28, a complete absorbing circuit is formed, and may be traced as follows: the metallic elements of loud speaker 28, capacity couplings 31 and 32, leads 57 of the loud speaker in parallel, capacity coupling 57, a portion of coil 38, condenser 42 and battery 55 in parallel, and ground 56, by way of filament conductors 58. The ground 56 need not be supplied if the receiver has sufiicient capacity effect to form a counterpoise, as is apt to be the case when the set is shielded.

It is possible to provide an arrangement adapted to be connected to an existing receiver set without change, and secure the benefits of the present invention. Thus in Fig. 3, the receiver set 80 is shown, having the input terminals 81 and 82, and the output terminals 83 and 84. The lower input terminal 82 is connected to ground 85.

A device 86 is provided, having a radio frequency choke coil 87 wound with twin conductors, and having terminals 88 and 89 which are connected respectively to input terminals 81 and 82. The twin conductors of coil 87 form the connections between the output terminals 83 and 84, and the loud speaker 28. The input circuit of set 80 is coupled to coil 87, by the aid of terminals 88 and 89. A stopping condenser 90 is included in the coupling, so as to prevent short circuiting of any battery circuits in the receiver 80. Further condensers 91 and 92 can if desired be provided to by-pass radio frequency energy in theabsorbing circuit in addition to the inherent coupling between the twin conductors.

The absorbing circuit in this instance includes the metallic parts of loud speaker 28, capacitive couplings 31 and 32, condensers 91, 90, 92 corresponding to the capacity efi'ect betwen the two conductors of coil 87, to ground or other counterpoise 85. The energy absorbed in this circuit is passed to the receiver set 80 by the aid of the connections between coil 87 and terminals 81 and 82.

Fig. 4 is quite similar to Fig. 3, and shows a device 93 which can be connected to set 80. In this instance, however, by-pass condensers 94, 95, 96 and 97 are arranged symmetrically with respect to the radio frequency choke coil 87.

In Fig. 5, the receiver set 80 has one of its output terminals 84 connected to a ground 85 or other counterpoise, and the arrangement is further such that the leads 98 and the inherent capacity coupling between the windings of the audio frequency transformer 99 are included in the absorbing circuit. This effect is obtained by connecting loud speaker 28 to the transformer secondary 100, and by connecting the ungrounded input terminal 81 to the secondary 100, through capacity couplings 101 and 102. Thus the absorbing circuit, extending from loud speaker 28, includes secondary 100, the capacity coupling from secondary 100 to primary 103, and con ductors 98 to ground 85. The input ter-. minals 81, 82 of,the set 80 are coupled to this absorbing circuit, due to a connection between terminals 84 and 82, and the capacity couplings 101 and 102 from secondary 100 to terminal 81.

It is not essential to limit the invention to an adaptation of any particular element, such as the loud speaker, as a part of the absorbing circuit. In fact, other elements can very readily be utilized for the same purpose. Thus in Fig. 6, the amplifying and detecting apparatus is shown as including a tunable radio frequency circuit 104 to which such an absorbing circuit .can be coupled. The apparatus also includes the amplifier and detector stages indicated in general by such requires no further detailing. The conductors 108 are, however, arranged to form the coils 110, coupled to circuit 104, and as is common one of the battery terminals is grounded at 111. It is possible to omit ground 111 if the receiving circuits have sufficient capacity to form a counterpoise. Thus an absorbing circuit is formed, including element 107, coils 110, and ground 111.

Other conducting elements used in the system can be used also. In Fig. 7, I illustrate such further application, in connection with an amplifying and detecting system having a tunable radio frequency circuit 112. This circuit is connected in'the conventional manner to. the input side of the thermi nic amplifier 113, which has a filament 114. The output side is connected to further elements (indicated by rectangle 115), for further amplification and detection of the signal impulses imparted to circuit 112, and finally the amplified signal is passed to a translating device 116, such as head phone or loud speaker. There is indicated an A battery 117 or its equivalent for passing a heating current through filament 114:, and this battery with its connections, also serves as an absorbing circuit. For this purpose, the heating circuit is coupled (in this instance conductively) to the tunable circuit 112, as by the aid of a movable contact 118 leading directly from an adjustable portion of coil 119 in circuit 112, to one of the terminals of battery 117. The complete heating circuit thus includes the lower portion of coil 119, connection 120, filament 114, variable resistance 121, and choke coil 122. The absorbing circuit includes the battery 117, lower portion of coil 119, connection 120, and ground or other counterpoise 123.

It is to be understood that I do not desire to be limited to the forms of the invention described as it is obvious that other modifications based upon the common idea that a portion of the usual elements making up the amplifying and detecting system, such as the loud speaker or batteries, may be used to provide as absorbing circuit coupled to the input side of the receiver.

In the following claims, the term coupling or coupled is intended to be broad enough to cover any of the well-known forms of couplings, such as conductive, inductive, and capacitive couplings.-

I claim:

1. A radio receiving system having a circuit arranged to be affected by radio signal impulses, a translating device, and means associated with said circuit for converting the impulses so that they may operate the translating device, characterized by the fact that means are provided whereby a portion only of the associated means and the device operates as a capacity area for an absorbing system, and whereby signaling impulses absorbed thereby, operatively influence the cir-' cuit.

2. In a radio receiving system, a circuit adapted to receive radio signal impulses, means for converting said impulses into audio frequency signaling currents and means whereb an open absorbing circuit is formed, for picking up and transmitting radio frequency energy to said circuit. and whereby said open absorbing circuit utilizes a part of said converting means as one capacity area.

3. In a radio receiving system having an input side to which radio frequency energy is arranged to be passed, and an output side from which audio frequency signaling currents may be taken, a two conductor circuit extending from the output side, and a translating device connected tothe circuit, the two conductors beingformed to serve as an element in an open absorbing circuit to transm1t radio frequency energy to the input side, and to cause the translating device to serve aspne capacity area for said absorbing circu1 4. radio receivin system having an input side, a loud spea er and leads therefor formin a loud speaker circuit characterized by the act that the leads include a coil, and means are providedfor forming an open absorblng circuit that includes said coil, and that utilizes the loud speaker as a capacity area, said coil being so associated with the lnput slde as to pass to it the radio frequency energy picked up in the open circuit.

5. radio receiving system having an input side, a loud speaker and leads therefor forming a loud speaker circuit, characterized by the fact that the leads include a coil wound with both leads to form a substantially noninductive element in the loud speaker circuit and forming an open absorbing circuit that includes said coil and that utilizes the loud speaker as a capacity area, said coil being so associated with the input side as to pass to it the radio frequency. energy picked up in the open circuit.

6. In a radio receiving system, means for converting radio frequency signal impulses into audio frequency currents, a translating device arranged to be affected by said currents, and means whereby the capacity area of the translating device with respect to a counterpoise is utilized to form an absorbing circuit for radio frequency energy and to affect with said energy, the converting means.

7. In a radio receiving system having a radio frequency input side and an audio frequency output side, a transformer having a winding arranged to transmit such radio frequency signaling impulses tothe input side, that is directly transferred to the output side from the natural medium, and another winding connected to the output side, and neutralized against transmission of audio frequency energy to the first winding.

8. In a radio receiving system having a radio frequency input circuit and a loud speaker circuit, a radio frequency transformer located in the loud speaker circuit and associated with the input circuit in such manner as to pass to it, radio frequency energythat is directly picked up by the loud speaker circuit from a natural medium.

9. In a radio receiving system, means capable of being affected by radio frequency energy, means for convert-ing said energy into readily perceptible form, both said means including units cooperating in the system, means whereby one or more of said units, independently of its normal connections,

transmits radio frequency energy intercepted thereby directly from a natural medium to the means that 1s capable of being affected by radio frequency energy.

10. In a radio receiving system, means capable of being affected by radio frequency energy, means for converting said energy into readily perceptible form, said converting means including a unit having a conducting surface of considerable area, means for forming an absorbing circuit in which circuit said unit serves as a capacity area as regards the rest of the system,and means whereb radio frequency energy directly transferre to the absorbing circuit independently of its normal connections to the system, is impressed upon the means capable of being affected by radio frequency energy.

11. A receiving system having the following three essential parts: (1) a radio frequency system comprising one or more radio requency circuits that is arranged to transmit radio frequency signals; (2) a system for modifying these signals; and (3) a system to which the modified signals are passed, characterized by the fact that means are provided whereby at least a.portion of systems (2) and (3), to the exclusion of system 1) forms a capacity area for an open absor ing circuit that is capable of picking up radio frequency energy, and whereby such energy is passed to system-(1) 12. A receivin system having the following three essential parts: (1) a radio frequency system comprising one or more radio frequency circuits that is arranged to transmit radio frequency signals; (2) a system for modifying these signals; and (3) a system to which the modified signals are passed, characterized by the fact that means are provided whereby a portion of the receiving system, exclusive of the radio frequency circuits of system (1) forms a capacity area for an open absorbing circuit that is capable of picking up radio frequency energy, and whereby such energy is passed to system (1) 13. A receivin system having the following three essential parts: (1) a radio frequency system comprising one or more radio frequency circuits that is arranged to transmit radio frequency signals; (2) a system for modifying these signals; and (3) a system to which the modified signals are passed, said system including a translating device for converting the modified signals into a perceptible form, characterized by the fact that means are provided whereby said translating device alone forms one capacity area for an open absorbing circuit that is capable of picking up radio frequency energy, and whereby such energy is passed to system (1) 14. A receiving system having the following three essential parts: (1) a radio frequency system comprising one or more radio frequency circuits that is arranged to transmit radio frequency signals; (2) a system for modifying these si' als; and (3) a system to which the mod ed signals are passed,

said system (3) including a translating'device for converting the modified signals into a perceptable form, characterized by the fact that means are provided whereby said translating device alone forms one capacity area for an open absorbing circuit that is capable of picking up radio frequency energy, and whereby such energy is passed to system (1), said means including a pair of conductors connected to the translating device for conducting to and from it, the modified signaling currents, said conductors being formed frequency coil to transmit the energy picked up by the open absorbing circuit, to system 15. A radio receiving system, having a radio frequency input circuit, a signal modifying means, and an audio frequency output circuit, characterized by the fact that means are provided whereb the radio frequency energy transferred directly from a natural medium to the audio frequency circuit acting as an absorbing circuit independently of its normal connectlons to the system is impressed upon the input circuit.

16. A radio receiving system, having a radio frequency input circuit, a signal modifying means, and an audio frequency output circuit, characterized by the fact that means are provided whereby at least a part of the audio frequency circuit forms a capacity area for an open absorbing circuit, and whereby radio frequency energy directly transferred to said absorbing circuit from a natural medium is impressed upon the input circuit.

17. In a radio receiving system, in combination, a receiver having a radio frequency input circuit, detecting and amplifying tubes, and an audio frequency out-put circuit, means connected by leads to the receiver for supplying operating energy to the tubes, means connected by leads to the out-put circuit to produce audible signals, one of said means independently of its normal connections to the receiver, operating together with its leads as an antenna, a portion of the leads to said one means being formed into acoil which serves as a primary winding of a radio frequency transformer to supply radio frequency energy to the input circuit of the receiver.

18. In a radio receiving system, in combination, a receiver comprising a radio frequency receiving circuit, radio frequency amplifying means, detecting means and audio frequency amplifying means, a loud speaker having leads connected to the audio frequency amplifying means, said loud speaker and its leads performing the function of an antenna, said leads being coupled to the radio frequency receiving circuit so that energy into a twin conductor coil that forms a radio" picked up from a natural medium by the loud speaker and its leadsmdependently of energy produced by the audio frequencyamplifymg means is transmitted to the receiving circuit.

19. In a radio receiving system, in combination, a receiver having a radlo frequency input circuit and an audlo frequency out-put circuit, detecting and amplifying tubes for I connected by lea s to the receiver for supplymg operating ener to the tubes, means connected b leads tot e outut circuit to produce au' 'ble signals, one 0 said means beingcoulpled to the radio frequency input circuit antenna, the coup operating toggther with its leads as an g means includin a coil wound to form an element substantia y noninductive with respect to the-currents other than radio frequency carried thereby.

21. A radio receiving system comprising in combination, a receiver having a radio frequenc input circuit, detecting and amplifying tu s, and an audio frequency out-put clrcuit, means connected by leads to the receiver for supplying operating energy for the tubes means connected by leads to the out-put circuit to roduce audible signals, one of said means aving in addition to its normal connections to the receiver, couplin to the radio frequency input circuit and operating together with its leads as an antenna.

22. In a radioreceivin system, a receiver having thermionic ampli ying and detecting apparatus, means including a circuit for supplying operating energy to said apparatus, means lncluding a circuit for rendering the amplified and detected signals audible, a unit possessing substantial impedance at the radio frequencies to be received inserted in the circuit of one of said means and coupling apparatus whereby the radio fr uency potentials induced in said unit by e ectromagnetic waves intercepted by said one means acting together with its lea'ds as an antenna are passed to the radio frequency input side of the receiver. Y

23. In combination, a radio receiver, a

loud speaker having metallic parts, means connecting said radio receiver and loud speaker for energizing the latter, and an antenna circuit for said receiver including mama at least someof said metallic parts as a capacitgearea and said means, said antenna circuit ing'operatively connected with said receiver totransfer ener thereto..

HARO F. ELLIOTT. v 

